Indicator tube for displaying a plurality of characters



June 23, 1970 s, cHms ET AL v 3,517,257

INDICATOR TUBE FOR DISPLAYING A PLURALITY OF CHARACTERS Filed Sept. 25, 1967 2 sheetssheefi 1 L J A g I VOLTAGE 8 +v k fi 1 I m I Lulu i *T (D 85 LVV V I..] s u B V INVENTORS. Fig. 4 SAUL KUCHINSKY ROGER W. WOLFE ATTORNEY.

June 23, 1970 s, uc s y ET AL 3,517,257

INDICATOR TUBE FOR DISPLAYING A PLURALIIY OF CHARACTERS Filed Sept. 25, 1967 2 Sheets-Sheet 2 A1 g I A2 3 5O 350 50 ($2) ffw m o o 5 o o o Fig. 5

I I VOLTAGE PULSES u 1 +V 7 gr; :A1O A 2 n A TIME I, flg- I I 0 V \J U I g; (:2 1 U U o I INVENTORS. SAUL KUCHINSKY ROGER W. WOLFE ATTORNEY United States Patent 3,517,257 INDICATOR TUBE FOR DISPLAYING A PLURALITY 0F CHARACTERS Saul Kuchinsky, Somerville, and Roger W. Wolfe, Plainfield, N.J., assignors to Burroughs Corporation, Detroit,

Mich., a corporation of Michigan Filed Sept. 25, 1967, Ser. No. 670,258 Int. Cl. G06f 3/14 US. Cl. 315-169 5 Claims ABSTRACT OF THE DISCLOSURE The disclosure is of an indicator tube adapted to display one or two characters at a time and including a plurality of parallel plates arrayed in a stack but electrically insulated from each other. Each 'plate is of metal and comprises, essentially, a frame which carries two BACKGROUND OF THE INVENTION One type of commercial numerical indicator tube includes ten separate cathode numerals in the'form of the numbers 0 to 9 mounted in a stack insulated from each other and in operative relation with an anode electrode. Tubes of this type, such as the 6844A Nixie tube made by Burroughs Corporation, are mass-produced with ease and have come into wide use. However, initially,

the problems of mounting ten delicate cathodes'in a stack in conjunction with an anode and'other elements were serious deterrents to mass production.

Although these tubes are now relatively easy to manufacture, they have some limitations which, though not generally serious, prevent them from performing some desirable functions. For example, there are many applications in which it would be desirable to be able to display two numerals side-by-side in the same tube envelope. However, the above-described tube construction cannot be readily adapted to perform this function.

SUMMARY OF THE INVENTION Briefly, the present invention provides an indicator tube which comprises a gas-filled envelope which contains a cathode electrode structure made up of conductive plates, each of which carries two numerals spaced apart with a shield between them. The corresponding numerals in the plates are vertically aligned to form two groups, with each group having its own anode electrode. By

applying properly phased pulses to selected cathode plates and to the anodes, two numerals, one in each stack, can be caused to glow at the same time.

DESCRIPTION OF THE DRAWING In the drawing: FIG. 1 is a sectional elevational view of an indicator tube embodying the invention;

FIG. 2 is a plan view of two cathode plates of the type used in FIG. 1;

FIG. 3 is a sectional view along the line 33 in FIG. 1;

FIG. 4 shows the relationship between two voltage waves used to operate the tube of FIG. 1;

FIG. 5 is a schematic representation of the tube of FIG. 1 and a circuit in which it may be operated; and

3,517,257 Patented June 23, 1970 rice FIG. 6 shows the relationship between the various voltages present in the circuit of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An indicator tube 10 embodying the invention includes the usual envelope 20 which has a viewing window 26 and a base or stem 30 which carries a plurality of electrical contact pins 40 which extend into the envelope. The envelope 20 contains a suitable atmosphere such as neon, argon, or the like for supporting cathode glow.

The electrode assembly for the tube 10 includes a plurality of metallic plates 50 which are suitably etched or stamped so that each, in effect, comprises a frame which carries two metallic electrodes 60, 62 in the form of numerals spaced apart side by side and secured to opposite edges of the frame. The numerals are to be operated. as cathodes and to exhibit cathode glow, and they are so positioned that two separate stacks of cathode numerals are provided, as can be seen clearly in FIG. 1.

In the tube 10, the plates 50 are suitably mounted and supported, for example, on selected ones of the pins 40 which are properly insulated for this purpose. In one suitable arrangement shown in FIG. 3, four insulated tube pins 40', suitably oriented, extend through holes in the corners of the plates 50. Suitable insulating spacers 70' are provided on these support posts (FIG. 1) between the cathode plates 50', and a metallic or insulating shield member is inserted vertically into the stack of plates between the two stacks of cathode numerals. This plate comprises a shield between the stacks of cathodes to prevent interaction between them.

The tube 10 also includes separate anode electrodes and 100, one for each stack of cathodes. Each anode structure might comprise a pair of screens, one at the top and one at the bottom of each group of cathodes. Alternatively, the anode screens might be U-shaped so that each can enclose the top, bottom, and side of its stack of cathodes as shown in FIG. 1. Other suitable anode arrangements will occur to those skilled in the art. The anodes might be held in place by the cathode support posts 40", with suitable insulating spacers 70 being provided and with locking eyelets being provided on the upper ends of the posts.

The tube 10 is operated with A.C. potential so phased that one anode and one cathode in its stack of cathodes have a maximum potential difference between them so that the cathode is caused to exhibit cathode glow. The frequency of the applied potential is sufficiently high so that the cathode appears to exhibit steady glow. Typical useful voltage pulse waves A and B are shown in FIG. 4. The pulse waves A and B are exactly opposite in phase and have the same frequency. It can be seen that, at times T, the maximum potential difference exists 'between A and B, and it is at these times that the cathode glows. Operating potentials might be applied simultaneously to each anode and one associated cathode so that two numbers can be displayed at the same time.

One specific circuit for operating tube 10 is shown in FIG. 5 wherein the tube 10 and circuit are shown schematically. In the circuit, an input power source is coupled to a transformer having primary winding and secondary winding 190. The secondary winding has one end 200 connected to the cathode and anode of parallel, oppositely oriented diodes 210 and 220, respectively. Diode 210 has its anode connected to anode 100, and diode 220 has its cathode connected to anode 90. Similarly, the other end 250 of the secondary winding 190 is connected to the anode and cathode of parallel, oppositely oriented diodes 260 and 270, respectively. The cathode of diode 260 is connected to a suitable switch mechanism 310 so that it can be selectively connected to one of the cathodes associated with anode 100, and the anode of diode 270 is connected to a suitable switching mechanism 320 so that it can be selectively connected to one of the cathodes associated with anode 90.

A resistive path 330 is connected across the secondary Winding 190, and a center tap 340 thereon is connected through separate resistors 350 to each of the pairs of cathodes or cathode plate 50 in tube 10. This arrangement serves to maintain the potential of the off cathodes at a ground or neutral reference point and prevent unwanted off cathode glow.

With these circuit connections, the voltage relationships shown in FIG. 6 are present at each of the anodes and at a selected cathode. It is to be noted that the potentials on each anode and one of its cathodes are opposite in phase whereby sufficient potential is applied between each anode and one of its cathodes so that the cathode can glow.

In a detailed consideration of the operation of the invention, if it is desired, or if the system applies such signals that only one cathode is caused to glow, then simultaneous positive and negative pulses are applied to an anode, for example anode 90, and to a selected cathode 60, with the peak-to-peak voltage between the two electrodes being sufiicient to cause the cathode to glow. To cause two cathodes 60 and 62 to glow simultaneously using the circuit of FIG. 5, switch 320 is connected to a cathode 60 and switch 310 is connected to a cathode 62. At one instant, a positive pulse is coupled from end 200 of secondary winding 190 of transformer 170 through diode 220 to anode 90, and a negative pulse is coupled from end 250 of winding 190 through diode 270 to the selected cathode 60. The peak-to-peak voltage between the anode and cathode is sufiicient to cause the cathode to glow. When the secondary winding 190' reverses and end 250 becomes positive and end 200 becomes negative, then anode 100 receives a positive pulse, and the selected cathodes 62 receives a negative pulse and the cathode 62 glows. The frequency of these polarity changes appearing on winding 190 is such that the two selected cathodes appear to glow simultaneously.

What is claimed is:

1. A multiple cathode indicator display tube comprising an envelope containing an ionizable gas capable of supporting cathode glow,

a plurality of cathode plates arrayed in a stack in said envelope and insulated from each other, each plate comprising a metal frame to which are secured first and second coplanar, spaced-apart metal cathode electrodes which are in the form of characters such as numerals, letters, or the like,

said first cathodes being vertically aligned in a first stack and said second cathodes being vertically aligned in a second stack, a first anode electrode associated with said first stack of cathode electrodes and a second anode electrode associated with said second stack of cathode electrodes,

and shield means positioned between said first and an envelope containing an ionizablegascapable of supporting cathode glow,

a plurality of cathode plates arrayed in a stack in said envelope and insulated from each other, each plate comprising a metal frame to which are secured first and second coplanar, spaced-apart metal cathode electrodes which are in the form of characters such as numerals, letters, or the like,

said first cathodes being vertically aligned in a first stack and said second cathodes being vertically aligned in a second stack,

a first anode electrode associated with said first stack of cathode electrodes and a second anode electrode associated with said second stack of cathode electrodes,

shield means positioned between said first and second stacks of cathode electrodes and said first and second anode electrodes to separate the stacks of cathodes and their anodes from each other, and

circuit means coupled to each anode and to each cathode in said two stacks for applying firing potentials first to said first anode and a selected associated first cathode, respectively, and then to said second anode and a selected associated second cathode, respectively,

said potentials being applied at such a frequency that two cathode portions can be made to appear. to glow at the same time.

3. The system defined in claim 2 wherein said circuit means includes a transformer having primary and secondary windings, said second winding having one end connected through a first diode oriented in one direction to said first anode and through a second oppositely oriented diode to means for contacting each of said second cathodes,

the other end of said secondary winding being connected through a third diode oriented in said one direction to said second anode and through a fourth oppositely oriented diode to means for contacting each of said first cathodes.

4. The tube defined in claim 1 wherein each anode electrode comprises a generally cup-shaped member which encloses one cathode of each plate.

5. The tube defined in claim 1 wherein each anode electrode comprises a generally cup-shaped member which encloses one cathode of each plate, at least one portion of each anode comprising a screen through which glowing cathodes can be viewed.

References Cited UNITED STATES PATENTS 3,188,509 6/1965 Var der Berg 3l3l09.5 3,090,893 5/1963 Reaney 3l5l35 3,114,860 12/1963 Stutsman 315169 3,141,093 7/1964 Solomon 250213 3,327,163 6/1967 Blank 315169 JOHN W. HUCKERT, Primary Examiner S. BRODER, Assistant Examiner US. Cl. X.R. 3l3--217 

